Silicon photodiodes can be used to detect UV (ultraviolet) radiation having a wavelength in the range from 200 nm to 400 nm. Absorption in plastic or glass used for conventional optical packages prevents the full range of ultraviolet light from reaching the photodiode inside the package.
US 2006/0038249 A1 discloses a UV sensor apparatus comprising a cathode layer and anode layers formed at a surface of the cathode layer. A section of the cathode layer that is located between the pn-junctions formed by the cathode layer with two of the anode layers is provided as light-receiving region.
U.S. Pat. No. 8,084,728 B2 discloses an optical sensing device with multiple photodiode elements and a multi-cavity Fabry-Perot ambient light filter structure. The device provides a blocking of infrared light for wavelengths in the range from 700 nm to 1100 nm.
US 2009/0184254 A1 discloses an ultraviolet sensor comprising a pair of photodiodes, in which p+-type and n+-type layers formed in silicon are separated by a thin layer of low doping concentration. A filter film comprising silicon nitride is formed above one of the photodiodes to transmit radiation having at least a first UV wavelength. A sealing layer which covers the other photodiode and the filter film transmits radiation having at least a different second UV wavelength.
Electrically conductive interconnects leading through the semiconductor body of a semiconductor device are known as through-wafer vias or through-substrate vias. Semiconductor devices comprising through-wafer vias or through-substrate vias are disclosed in US 2010/0123254 A1, US 2010/0314762 A1, US 2011/0260284 A1 and US 2012/0286430 A1.